Children's Special Vulnerabilities

Children are not just little adults. They are different in many ways, particularly with regard to their exposures and responses to the environment. As nurses, we know that infants and young children breathe more rapidly than adults. This increase in respiratory rate may translate into a proportionately greater exposure to air pollutants. While infants' lungs are developing, they may also be susceptible to environmental toxicants. Behaviors characteristic of early childhood also affect a child's exposure to toxicants. In the first years of life, the young child spends hours close to the ground where he or she may be exposed to toxicants in dust, soil and carpets as well as to pesticide vapors in low-lying layers of air. (Visit www.cehn.org/cehn/WhatisPEH. html. )

Infants and young children drink more fluids per body weight than adults, potentially increasing their dose of contaminants found in their drinking water, milk, and juices (particularly pesticides). For example, the average infant's daily consumption of six ounces of formula or breast milk per kilogram of body weight is equivalent to an adult male drinking 50 eight-ounce glasses of milk a day (Bearer, 1995). Children also eat more per body weight and they eat different proportions of food. How many adults could eat the same amount of raisins pound-for-pound as the average two-year-old? Children consume many more fruits and fruit juices than adults, which may result in larger doses of exposure to pesticide residues.

Children play on the floor, the grass, and the playground, placing them at increased risk for exposure to toxic chemicals that may be applied to or settle on the floors or ground, including lead-based paint dust, cleaning product residues, and horticultural/agricultural chemicals (fertilizers, herbicides, pesticides). The hand-to-mouth exploration of the infant and young child that helps them to learn about their world also places them at higher risk of exposures. This is particularly true in the case of lead-based paint dust when it is present in houses and schools. Because metabolic systems are still developing in the fetus and child, their ability to detoxify and excrete toxins differs from that of adults. This difference is sometimes to the child's advantage, but more frequently they are not able to excrete toxins as well as adults, and thus are more vulnerable to them.

Children's bodies also function differently than adults. The rate at which children absorb nutrients from the gastrointestinal tract is likewise different than the rate for adults, a fact that can impact their exposure to toxicants. For example, children have a greater need for calcium for bone development than do adults and will absorb more of this element when it is present in the gastrointestinal tract. When lead has been ingested into the gut, however, the body will absorb it in place of calcium. Consequently, an adult will absorb 10 percent of ingested lead, while a toddler will absorb 50 percent of ingested lead (Bearer, 1995). And finally, some of the protective mechanisms that are well developed in adults, like the blood-brain barrier, are immature in young children, thereby making them more vulnerable to the effects of some toxic chemicals.